I can see I need to do some convincing regarding the expense and 
production limits of Paleo foods. Consider what Loren Cordain wrote:

"Fresh fruits and vegetables cost more than beans and white rice. Lean 
pork tenderloin and turkey breasts are more expensive than potatoes and 
bread. The starchy foods of the Agricultural Revolution are the world's 
cheap foods. Grains, legumes, and tubers are the starchy foods that have 
allowed our planet's population to balloon to more than 6 billion. ... 
Without them, the world could probably support one-tenth or less of our 
present population [which at the time of the book's publishing in 2001 
would have come to about 620 million]; without agriculture's cheap starchy 
staples, it is no exaggeration to say that billions of people worldwide 
would starve.

It is unfortunate that for most of the world's people, the diet to which 
they are genetically adapted now lies beyond their financial reach. The 
foods decreed by our genetic heritage and the foods we all ate before the 
Agricultural Revolution have now become the elite foods of wealthy, 
priviledged countries." (The Paleo Diet, p. 217). 

Cordain's estimate that 600 million (rounded for simplicity) or fewer 
people could be supported by Paleo-like foods takes into account that 
agriculture and technology would be used to produce most of the food. 
That's clearly how he gets 600 million instead of the 100 million figure 
that is the most generous estimate of true hunter-gatherers that the 
planet could support. The only reason I mentioned the hunter gatherer 
carrying capacity estimates earlier was that I didn't have an estimate of 
the carrying capacity of agricultural Paleo-like foods because I hadn't 
noticed Cordain's figure. Now that I have a credible estimate, if anyone 
has a better one I hope you will share it with us.

Yes, agricultural production of Paleo-like foods can be increased to a 
certain extent, but not sufficiently to feed anywhere near 6.5 billion 
people. If Cordain's estimate is correct, than if even 11% of the world's 
population decides that they want Paleo-like foods, the demand will 
exhaust the supply, and the prices will have skyrocketed long before that 
point.

No matter how you slice it, buying fresh meats, seafood, fruits and 
vegetables will cost more overall than buying grains, legumes, tubers and 
milk. Sure, you can find ways to economize and buy meat on special, but 
you could also economize even more by buying grains in bulk. Why is it 
that the poorest nations in the world eat tons of grains like rice? Rice 
is obviously cheaper and more plentiful than meat.

Growing Paleo-food gardens and fruit and nut trees is a good suggestion 
which I appreciate, but for those who don't own land or a greenhouse it is 
not a solution. Not eating out, or taking food with you are also good 
tips, where possible, but they still won't feed 6.5 billion people, or 
even 650 million, on Paleo-like foods. I guess those of us in the know 
will have to try to acquire land for gardens, fruit trees, hunting and 
fishing, and weapons with which to defend ourselves against those who 
would try to steal our food should the price increases make them very 
valuable. Or save and invest our money so we will have enough should Paleo-
like food prices rise. Then pity those who do not have gardens or 
plentiful savings.